MC908AP32CFBE Freescale, MC908AP32CFBE Datasheet - Page 285

• Manufacturer Part Number: MC908AP32CFBE
• Manufacturer: Freescale

Specifications of MC908AP32CFBE

• Cpu Family: HC08
• Device Core Size: 8b
• Frequency (max): 8MHz
• Interface Type: SCI/SPI
• Total Internal Ram Size: 2KB
• # I/os (max): 32
• Number Of Timers - General Purpose: 4
• Operating Supply Voltage (typ): 3.3/5V
• Operating Supply Voltage (max): 5.5V
• Operating Supply Voltage (min): 2.7V
• On-chip Adc: 8-chx10-bit
• Instruction Set Architecture: CISC
• Operating Temp Range: -40C to 85C
• Operating Temperature Classification: Industrial
• Mounting: Surface Mount
• Pin Count: 44
• Package Type: PQFP
• Program Memory Type: Flash
• Program Memory Size: 32KB
• Lead Free Status / RoHS Status: Compliant

Chapter 19
Computer Operating Properly (COP)
19.1 Introduction
The computer operating properly (COP) module contains a free-running counter that generates a reset if
allowed to overflow. The COP module helps software recover from runaway code. Prevent a COP reset
by clearing the COP counter periodically. The COP module can be disabled through the COPD bit in the
configuration register 1 (CONFIG1).
19.2 Functional Description
Figure 19-1
The COP counter is a free-running 6-bit counter preceded by a 12-bit prescaler counter. If not cleared by
software, the COP counter overflows and generates an asynchronous reset after 2
ICLK cycles, depending on the state of the COP rate select bit, COPRS, in the CONFIG1 register. With
a 2
value to location $FFFF before an overflow occurs prevents a COP reset by clearing the COP counter
and stages 12 through 5 of the prescaler.
Freescale Semiconductor
13
INTERNAL RESET SOURCES
– 2
(COPRS FROM CONFIG1)
4
(COPD FROM CONFIG1)
RESET VECTOR FETCH
ICLK cycle overflow option, a 88-kHz ICLK gives a COP timeout period of ~93ms. Writing any
STOP INSTRUCTION
shows the structure of the COP module.
COPEN (FROM SIM)
COPCTL WRITE
COPCTL WRITE
COP RATE SEL
COP DISABLE
RESET
ICLK
MC68HC908AP Family Data Sheet, Rev. 4
Figure 19-1. COP Block Diagram
12-BIT COP PRESCALER
COP CLOCK
COP COUNTER
6-BIT COP COUNTER
CLEAR
RESET STATUS REGISTER
RESET CIRCUIT
18
– 2
4
or 2
13
– 2
4
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